(1) Field of the Invention
The present invention relates to a device for launching and recovering a drone, and to the associated aircraft. The invention thus lies in the technical field of aircraft.
(2) Description of Related Art
Aircraft include in particular helicopters that are of long autonomy but that are voluminous, expensive, and the subject of flying constraints for ensuring the safety of their occupants. Furthermore, in order to ensure the safety of its occupants, a helicopter must not fly in certain air spaces, for example when the ground relief is likely to lead to an accident or when the atmosphere is contaminated in particular by dangerous chemicals, bacteria, or indeed radioactive elements after an accident.
Drones are also known, i.e. aircraft that do not have an on-board pilot and that are of limited autonomy. Nevertheless, drones are of small size which means that they can fly close to dangerous ground relief, and they can be remotely controlled, e.g. in order to fly in an environment that is polluted and dangerous for people. Furthermore, the cost of a drone is much less than that of a helicopter. Under such circumstances, a drone may sometimes be considered as being a consumable, should it turn out to be difficult to recover and if recovery is not essential.
These two types of aircraft can thus be seen to be complementary.
It would be advantageous to fit an aircraft and in particular a helicopter with a drone that can be launched while the aircraft is in flight. The helicopter can then cover a relatively long distance in order to take the drone quite close to a zone that is to be investigated, possibly a zone that is not accessible to the helicopter for reasons associated with the safety of personnel on board the helicopter.
By launching a drone from a helicopter, limitations associated with the short autonomy of a drone are avoided.
Furthermore, it is advantageous to be able to recover the drone using the helicopter, e.g. in order to refuel it while it is carrying out its mission or else in order to recover equipment carried by the drone.
Nevertheless, it is found difficult to control the path followed by a drone in a zone that is disturbed by the wash from the lift rotor of a helicopter, both for launching the drone and also for recovering the drone, while also avoiding any risk of collision between the two aircraft. The lift main rotor of a helicopter has a stream of air passing therethrough, this stream of air greatly disturbing aerodynamic conditions within a zone over which the helicopter is flying. Furthermore, it can be understood that the lighter the drone, the greater the uncertainty concerning its flight path within the zone that is disturbed by the stream of air passing through the helicopter lift rotor.
In addition to the difficult air/flow conditions that are to be encountered close to a helicopter, it is onerous to provide a drone with accurate piloting means. Furthermore, such means are bulky and of non-negligible weight.
It is therefore very difficult to fly a drone close to a helicopter without risk after the drone has been launched from said helicopter or for the purpose of securing a drone to the helicopter.
It can be understood that it may also be difficult to fly a drone without risk in other circumstances, e.g. close to a ship or a building.
In the state of the art, devices are known for launching an aircraft from a moving platform. Such devices do not appear to be suitable for limiting the risk associated with flying a drone close to a helicopter and in particular in the stream of air passing through the lift rotor of the helicopter.
For example, document WO 2008/089432 discloses an aircraft for launching a drone that is attached to a parachute. After launching, the parachute becomes detached from the drone and the drone becomes autonomous.
Furthermore, devices exist that use anchoring hooks or simple nets for recovering the drones in flight. Such devices appear to be unsuitable for launching and recovering a drone that does not have accurate piloting means, and all the more so when flying close to a helicopter.
Similarly, approach methods are known for positioning a drone vertically over a landing zone. Reference may be made for example to document EP 1 645 505.
Furthermore, the state of the art also includes the following documents: EP 2 103 518 A2, US 2006/249623A1, FR 2 941 922 A1, U.S. Pat. No. 3,389,880 A, DE 3 206 299 A1, and U.S. Pat. No. 4,753,400 A.